Non-volatile flash memory cell with asymmetric threshold voltage

摘要

A non-volatile flash memory cell with an asymmetric threshold voltage comprises a channel region, a doping region, a floating gate, and a control gate. The channel region is located in a surface of a substrate and between a source and a drain in the substrate. The doping region is located in one side of the channel region near the source and a plurality of a first dopants and a plurality of a second dopants are doped in the doping region and the substrate with the same conductivity. The control gate is located over the channel region and insulated to the channel region. The floating gate is located between the channel region and the control gate, and is simultaneously insulated to each other. The present flash memory cell still can extend to divide the channel region to a first channel region near the source and a second channel region near the drain without using the doping region. Moreover, a threshold voltage of the first channel region is larger than a threshold voltage of the second channel region.